Guo M, Chorover J, Rosario R, Fox R H
Department of Agronomy, The Pennsylvania State Univ., University Park 16802, USA.
J Environ Qual. 2001 Sep-Oct;30(5):1699-709. doi: 10.2134/jeq2001.3051699x.
Passive leaching by rainfall and snowmelt is a popular method to treat piles of spent mushroom substrate (SMS) before its reuse. During this field weathering process, leachate percolates into the underlying soils. A field study was conducted to examine the chemistry of SMS leachate and effects of infiltration. Two SMS piles were deposited (90 and 150 cm in height) over a Typic Hapludult and weathered for 24 mo. Leachate was collected biweekly using passive capillary samplers. The SMS leachate contained high concentrations of dissolved organic carbon (DOC; 0.8-11.0 g L(-1)), dissolved organic nitrogen (DON; 0.1-2 g L(-1)), and inorganic salts. The pH, electrical conductivity, and acid neutralizing capacity were 6.6 to 9.0, 21 to 66 ds m(-1), and 10 to 75 mmolc L(-1), respectively. Inorganic chemistry of the leachate was dominated by K+, Cl-, and SO24-. Leachate DOC was predominantly low molecular weight (<1000 Da) organic acids. During 2 yr of weathering, the 90-cm SMS pile released (per cubic meter of SMS) 3.0 kg of DOC, 1.6 kg of dissolved N, and 26.6 kg of inorganic salts. The 150-cm pile released (per cubic meter of SMS) 2.8 kg of DOC, 0.7 kg of dissolved N, and 13.6 kg of inorganic salts. The 150 cm pile retained more water and exhibited lower net nitrification compared with the 90-cm pile. The top 90 cm of soil retained 20 to 89% of the leachate solutes. Weathering of SMS in piles of 90 cm depth or greater may adversely affect ground water quality.
通过降雨和融雪进行被动淋溶是在再利用之前处理成堆的废弃蘑菇培养料（SMS）的一种常用方法。在这个田间风化过程中，渗滤液会渗入下层土壤。进行了一项田间研究，以检查SMS渗滤液的化学性质和渗透作用的影响。在一个典型的强发育湿润淋溶土上堆放了两堆SMS（高度分别为90厘米和150厘米），并进行了24个月的风化。使用被动毛细管采样器每两周收集一次渗滤液。SMS渗滤液含有高浓度的溶解有机碳（DOC；0.8 - 11.0克/升）、溶解有机氮（DON；0.1 - 2克/升）和无机盐。pH值、电导率和酸中和能力分别为6.6至9.0、21至66毫西门子/米和10至75毫摩尔碳/升。渗滤液的无机化学以钾离子、氯离子和硫酸根离子为主。渗滤液中的DOC主要是低分子量（<1000道尔顿）的有机酸。在2年的风化过程中，90厘米高的SMS堆每立方米释放出3.0千克的DOC、1.6千克的溶解态氮和26.6千克的无机盐。150厘米高的堆每立方米释放出2.8千克的DOC、0.7千克的溶解态氮和13.6千克的无机盐。与90厘米高的堆相比，150厘米高的堆保留了更多的水分，并且净硝化作用较低。土壤表层90厘米保留了20%至89%的渗滤液溶质。90厘米及以上深度的SMS堆风化可能会对地下水质量产生不利影响。
